Internal-combustion engine



May 20, 1930.

C. DAVIDSON INTERNAL COMBUSTION ENGINE Filed Jan. '7, 1929 INVENTOR C/infofl Day/0 50 A TTORNE YS I Patented May 20, 1930 UNITED STATES PATENT? OFFICE INTERNAL-COMBUSTION ENGINE Application filed January 7, 1929. Serial No. 330,819.

My invention relates to engines of the internal combustion type and particularly to the means for supplying the fuel to the eng There are several characteristic cycles which govern the operation of the various internal combustion engines. These are the Beau de Rochas cycle, or, as it is more commonly known, Otto cycle, the Sabathe, or

mixed, cycle, and the Diesel cycle. A primary distinction may be drawn between engines operating upon these several cycles according to the relative volatility of the fuel supplied. Usually an engine operating on the Otto cycle burns a relatively highly volatile fuel, while one burning a relatively nonvolatile fuel may be considered as operating on the Diesel cycle. The Sabathe cycle is .usuall confined to those engines operating upon uels of slightly greater volatility, than that of the fuel ordinarily used in a Diesel engine, while employing the Diesel method of combustion.

A further distinction may be drawn between these cycles according to the pressure and volume conditions existing in the cylinder when the combustion of the fuel takes place. In an Otto cycle the combustion occurs explosively with a relatively sudden rise during combustion is substantially constant, while the Sabathe cycle substantially combines both the explosive and constant pressure conditions.

The firing principle of the engines operating upon, or partially embodying, constant pressure ignition depends upon the compression of the air in the cylinder to such a pressure that ignition occurs, when the fuel is injected, because of the high temperature of the air due to compression. These engines are further particularly characterized by the absence of positive firing devices, as distinguished from the Otto cycle engines in which a positive firing device is provided.

In many respects the engine operating upon the Otto cycle present numerous advantages over the engines operating upon other cycles. The Otto cycle engine, by virtue of its lower 50 operating pressures, may be constructed with in pressure, in the Diesel cycle the pressure less weight er horse power with the consequent lower first cost, maintenance and depreciation. The lightness of the engine makes its use particularly expedient in many industries.

There is however, one disadvantage to which engines operating on the Otto cycle are subject. With the usual manner of engine fuel supply, a relatively highly volatile oil of rather constant character is required. This is an extremely severe handicap, for oils of this character usually sell at a premium and in many cases they cannot be obtained. This enforces the use of the heavy, bulky engines operating on other fuels.

In the engines operating upon the Otto cycle the fuel is usually vaporized in a carburetor and distributed, admixt with thle proper quantity of air, thru a manifold to each cyhnder. Many difliculties are experienced by this operation among which the greatest are probably the admission of unequal quantities of the fuel mixture to the several cylinders, and the partial condensation of the vaporized fuel in the manifold. These difficulties result in erratic and inefficient operation.

It is therefore an object of my invention to provide means for operating an internal combustion engine upon a relatively nonvolatile fuel.

Another object of my invention is to provide substantially even distribution of fuel to each cylinder of an Otto type engine.

A further object of my invention is to pro vide a simplified means of controlling the air and fuel admitted to a cylinder of an internal combustion engine.

The invention possesses other advantageous features; some of which, with the foregoing, will be set forth at length in the following description, where I shall outline in full, that form of the engine of my invention which I have selected for illustration in the drawings accompanying and forming part of the present specification. In said drawings I have shown one embodiment of my invention, but it is to be understood that I do not limit myself to such form, since the invention, as set forth in the claims, may be embodied in a plurality of forms.

In the drawings, to which I have made reference, Figure 1 is a plan view of a typical internal combustion engine with the device of my invention applied thereto.

Figure 2 is a partial cross section thru the typical engine along the line 22 of F igure 1.

Figure 3 is a partial cross section thru the typical engine along the line 33 of Figure 1.

In its preferred form, the internal combustion engine of my invention includes inlet and outlet valves in combination with an expansible chamber, a means for conducting a liquid form of fuel to the expansible chamher and there forming an explosive mixture, and electrically operated tiring means operated in a timed relationship with the operation of the valves and the admission of the fuel.

In the form of the invention disclosed in the drawing, an engine 6 is provided of a suitable type operating according to the four stroke Otto cycle. The engine is similarly proportioned and designed as one operating exclusively on gasoline or a similar light volatile hydrocarbon fuel. The engine is constructed with suitable inlet valves 7 and outlet valves 8. These are actuated by means of the rocker arms 9 and tappets 11 from a suitable cam shaft (not shown).

The introduction of fuel is accomplished by suitably forcing oil thru the pipe 16 from a convenient form of force pump or pressure reservoir (which are not shown) at suitable intervals. I preferably provide a separate pump to supply oil to each cylinder of the engine of my invention at a predetermined interval. This pump is suitably operated by the engine. The oil enters a passage 17 in a body 18 from a duct 19, which is in communication with the pipe 16. The body 18 is in direct communication with the vapor space of cylinder 21. The body is so located on the cylinder to give the most suitable dispersion of fuel in the cylinder. From the passage 17 the oil enters a chamber 22. To facilitate the manufacture of the device I fabricate a plug 23 which is conveniently secured into the body 18. The plug is manufactured with a s ecially threaded thimble 24 in one end t ereof. The plug is further expediently provided with the upper conical bore 26 and the lower conical bore 27 which are suitably formed to facilitate the discharge of fuel therefrom.

As means for regulating the quantity of oil passing into the cylinder, a needle valve 28 is preferably used, which, together with the upper conical bore 26, serves as a means for regulating the quantity of 011 discharged into the cylinder. The positionin of the needle valve with respect to the conical bore is suitably adjusted by means of the screw threads 31 formed upon the stem of the valve and in the body 18. A packing gland 32 and gland nut 33 expediently serve to render the valve tight.

Situated between the passage 17 and the duct 19 is a ball check 34, which allows conveniently the passage of oil into the cylinder only during the desired interval, and prevents communication of pressure from the cylinder to the oil line 16.

The quantity of air admitted is varied conveniently by means of the butterfly valve 41 placed in the inlet port 42. The inlet port is in communication with the inlet valve 7. The ratio of fuel and air admitted is kept substantially constant by rendering the quantity of air admitted variable with the change in quantity of fuel, thus securing a substantially higher efficiency than where a constant quantity of air is admitted. To accomplish this expediently the valve 41 is so positioned with respect to the needle valve 28 that they are conveniently made coactive by means of gears 43 and 44. These are respectively positioned upon the butterfly valve and the needle valve. The gears are suitably proportioned to vary correctly the quantity of the fuel discharged to the quantity of air admitted. To alter conveniently the quantity of air and fuel admitted to the several cylinders, I provide the several arms 45, aflixed to the stemsof each of the butterfly valves, and joined together, to be mutually coactive, by the bar 46.

In operation with a four stro e cycle engine of my invention the separate proportional charges of fuel and air are admitted, preferably, while the piston is making the suction stroke, but may be continued thru part or all of the compression stroke. The air is under preferably substantially atmospheric pressure. The fuel, however, is forced thru the pipe 16 and the several ducts and chambers in the body 18 under high pressure, approximating 2000 pounds per square inch. The passage thru the spirally threaded thimble imparts a whirling motion to the oil and upon its discharge from the lower conical bore it is substantially atomized because of the release of the pressure and the form of discharge. Turbulence within the cylinder effects its admixture with the air therein to form what may be termed an explosive mist of oil and air.

Upon completion of the suction stroke the explosive mist is compressed during the compression stroke. With the piston approaching the end of, or, at the top of, its stroke in the cylinder, the explosive mist is fired by some form of firing device present in the cylinder. Thus I have suitably provided the spark plug 47, which, in combina tion with suitable timing and electrical means, positively fires the fuel charge at a predetermined instant.

The expansion stroke now occurs during which useful work is taken from the exploded gases by the usual mechanical means, The gases are exhausted thru the exhaust valve urmg the next stroke. The cycle is then repeated.

As disclosed in my copendin application,

Serial No. 316,209, filed Octo er 31, 1928,

I supply to the engine of my invention a fuel substantially less volatile than that ordinarily used in engines of this ty e. The advantages attendant upon the a ility to use I such a fuel are manifest.

I claim:

1. In an internal combustion engine ins cluding a cylinder, means for injecting fuel into sald cy der, a shaft cooperatively associated with said injection means to control injection, a gear on said shaft, an air admission valve, a butterfly valve for controllin air passing to said admission valve a she cooperatively associated with the valve for controlling the position thereof, a gear on said last mentioned shaft, the gears cooperating to move the shafts to control fuel and air admitted to the cylinder.

2. In an internal combustion-engine including a cylinder,means for injecting fuel into Sand cylinder, a shaft cooperatively associ-. ated with said injection means to control injection, a gear on said shaft, an air admission valve, a butterfly valve for controlling air passing to said admission valve a shaft cooperatively associated with the valve for controlling the position thereof, a gear on said. last mentioned shaft in mesh with the first mentioned gear, and means for moving said gears to vary fuel and air admitted to the cylinder.

In testimony whereof, I have hereunto set in hand.

y CLINTON DAVIDSON. 

